Rebuild 2.0

Gold Leaf PrototypingThe “Rebuild 2.0” is a major overhaul of the Fusion:Guitar prototype. Several aspects of the original instrument quite didn’t satisfy me, and were due for an overhaul and further experimentation. Interestingly, the motivation for this overhaul comes from an invitation to present my work at CTM The New School for Design in New York City.

When I sat down to identify features I would like to improve, the following came up:

  1. Adding a near-traditional neck block to diminish vibration loss at the neck-body-joint.
  2. Using the new neck block construction to make the instrument collapsible for facilitating further experimentation and ease of transportation.
  3. Building a tail block with a cello spike to allow vertical performance posture.
  4. Building an extended interior frame that serves as an anchor for the forces from the neck.
  5. Closing all unneeded cavities of the top/soundboard.
  6. Creating a system to easily remove the soundboard to facilitate further experimentation.
  7. Reviewing and improving the membrane.

Unfortunately, some of the above points would take too much time to refine until the presentation (scheduled for the weekend of June 20th-23rd 2014). However, the most urgent issues are in the process of being addressed.

Neck block

The original prototype had no neck block whatsoever, and the neck was mounted to the body with 3 screws in various locations, and the use of an extended internal neck composed of several carbon fibre rods. While this internal neck did provide the rigidity to effectively counter string tension, it was unexpectedly weak in terms of torsional forces. As a result, there was a tremendous loss of vibrational energy between the body and the neck, and the sound of the instrument suffered.

Process FusionGuitar 001

The new neck block allows for several very useful features:

  • Improving sound through better anchoring in the body.
  • The possibility to use a bolt-on neck, permitting exchangeable prototype necks, fitting the guitar into overhead airplane storage for eliminating shipping damage risk.
  • Closing the neck access cavity and creating a more traditional guitar volume scenario.

The Internal Peg  Box

Once the possibility of creating a collapsible guitar  came about, it was time to rethink the peg box. The original prototype peg box was based on the lute peg box, with the goal to minimize weight. However, this type of peg box needs a lot of room and even creates the need for a custom guitar case – making the original prototype very hard to transport.

The idea that came to me was to move the entire peg box mechanism into the neck, creating something similar to a “headless” instrument. Since this experiment is still underway, I cannot make any conclusions as to how well it works. The design is quite complicated, and I am currently working on how to best route the strings on the back of the neck to each tuner. This style of neck has 2 interesting advantages:

  • Making the neck significantly easier to store safely for transport.
  • Moving the center of gravity of the instrument closer towards the musician’s lap.

As I was shaping the internal peg box, the question arose as to how the wood should be finished on its accessible inside. I decided to attempt a technique used by the lebanese Oud maker Nazih Ghadban that had caught my attention a long time ago – gold leaf. It took me many, many attempts; but finally I achieved a result that was somewhat satisfactory in terms of workmanship. I am very happy with this experiment, since it conveniently reflects a lot of light into the interior of the peg box – thus illuminating a space that would otherwise be relatively dark. This should help when changing strings on the planetary gear pegs.

Membrane

The major issues of the original membrane were that the chemicals involved where quite hazardous to work with, and the “”kitchen-compatible” technique didn’t quite provide the same tautness. So this time, experimentation and a new paper fabric enabled me to find a better technique to achieve a taut membrane while using only flour glue and Kinwashi paper. A finishing treatment with CPES (clear penetrating epoxy) and shellac resulted in nicely finished and translucent samples.

The issues that still have to be worked out at this point are:

  • Verify whether the new glue and fabric adhere well everywhere on the guitar skeleton.
  • Assess structure and aesthetics of fabric overlap.
  • Assessing how the CPES/shellac finish looks and feels on the finished body.

Revised Top and Through-Top Bridge

The new top will feature a revised sound hole shape, bracing pattern, and a through-the-top string fastening system. The latter is a necessity, since the Rebuild 2.0 will feature a travel friendly removable neck while not having a side port or sound hole of sufficient size to allow reaching into the instrument.

The gallery above shows a redwood top (Sequoia sempervirens) with an incredible flame and some beautiful speckle pattern. The last time I used this wood was in my thesis guitar, and it is only fitting that the Rebuild 2.0 follows the tradition of radical experimentation.

Process FusionGuitar 010

A draft of the new brace layout

The redesigned through-the-top string fastening system is inlayed into the top. Each string fastening insert is located where it best suits the bracing layout. This new spacing is also an experiment attempting to match the different string types to each other tonally. A saddle that aligns the strings will be necessary for this design, and I am quite curious how these new features will change the tone from the predecessor of this design, the Projektor Guitar.

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